This invention relates to a separator module for a stormwater gully chamber.
Conventional gullies under roadways and other paved areas comprise a chamber having inlet and outlet pipes which open into the chamber at a position above the bottom of the chamber. There may also be a top inlet, which provides access to the interior of the chamber through a grating provided at the roadway surface, for example in a gutter. In use, solids entering the chamber, whether from the inlet pipe or through the grating, collect under gravity in the base of the chamber and can be extracted at intervals by means of a suction pipe introduced into the chamber after removing the grating. Such gullies have a low separation efficiency. Furthermore, in the event of heavy storm flows, collected solids in the base of the chamber, and solids floating on the surface tend to be stirred up, and can pass into the outlet pipe.
A hydrodynamic vortex separator may be used to improve the separation efficiency of the gully. Such separators are suitable for removing sediment, litter and oil from surface water runoff.
FIG. 1 shows an example of a hydrodynamic vortex separator used in a stormwater gully, as disclosed in U.S. Pat. No. 7,344,636. The separator comprises an inlet compartment 3 and an outlet compartment 5 installed within a chamber 7. The inlet compartment 3 is connected to an inlet duct and the outlet compartment 5 is connected to an outlet duct. The inlet compartment 3 and the outlet compartment 5 are offset from one another around the circumference of the chamber 7 and are fluidically connected by a bypass duct 9.
An opening 11 is provided at the bottom of the inlet compartment 3 which serves as an inlet to the interior of the gully chamber 7. The inlet opening 11 is oriented so that inflowing liquid creates a circulating flow within the chamber 7 which assists in causing any solids within the incoming flow to accumulate and fall to the bottom of the chamber 7 or rise to the fluid surface depending upon their density. Similarly, the outlet compartment 5 has an opening which serves as an outlet from the interior of the chamber 7. The outlet opening is oriented so that outflowing liquid passes through the outlet opening in a direction opposite that of the circulating flow. The relative orientations of the inlet and outlet openings means that, even under conditions of heavy flow, solids will be swept past the outlet opening rather than leave the chamber.
A weir is provided between the inlet compartment 3 and the bypass duct 9 so that, in periods of heavy flow, only some of the flow entering the inlet compartment 3 will pass through the inlet opening 11, and the remainder will pass over the weir and through the bypass duct 9 directly to the outlet compartment 5.
Although the bypass duct 9 may be cut to an appropriate length so that the inlet and outlet compartments 3, 5 align with the inlet and outlet ducts, the bypass duct 9 must be made available in different radii of curvature to conform to chambers having different diameters. Further, the size, number and position of the ducts is restricted somewhat by this arrangement.
In addition, the inlet and outlet compartments 3, 5 and the bypass duct 9 limit the bypass capacity of the separator.
It is therefore desired to provide a separator module which addresses or alleviates some or all of these issues.